Infamous 'double Advent system'...

[real1shepherd]

Don’t laugh, for some of us, things don’t come too easily. Back in college in the early 70’s I bought a pair of Advents, a Kenwood receiver and a Thorens turntable. Then I was in a stereo shop in Miami one day, bumming (that’s all I could afford to do) and found the article on the ‘double Advent system’ by The Absolute Sound and Advent Corp's subsequent reply. That was my goal then, to take this cheap marvelous speaker to the next level.

Well as these things go, marriage, career, children etc….the concept was put on the back burner. Kept all the original gear though, including the speakers. Then I got divorced and was suddenly single again with new priorities. But when I was married, our music tastes were so wildly different, that no compromise could be had and thus no music was listened to. So I’ve had to push myself back into the habit of music listening, which isn’t too hard, pack rat that I am, I’ve kept all my old albums, some three hundred odd beasties maybe more.

Discovering ebay I bought another old set of Advents and the guy would not answer my emails and kept the money. Ebay did squat about it and so recently I tried again on a walnut veneered pair. They got here by Greyhound bus and were in spectacular shape-far better than my old ones. However the re-foam job was done improperly and mounted on the outside of the masonite ring, woofers not sealed etc. Sent for new surrounds and redid the whole thing myself including a better sealant for the woofers. Advent apparently used mortite, which is nothing more than a window-glazing compound. I found a product whose properties I liked better-comes in 1/4" caulk rope and is a black, poly product used in auto windows.

Anyway, I fused each speaker and set up the double Advent system in A+B mode with a hefty Onkyo receiver. Wow….what used to be speakers now became a wall of sound. Incredible and worth the wait I suppose, although 30 yrs is a bit much.

So…I have a couple of questions. First of all, how do I determine if all the speakers are in phase?? The other question is basically about the tweeter/crossover. One set has the newer replacement poly dome, black tweeters, but I didn’t buy the poly cap for the crossovers yet. When I was A/B-ing the two sets separately, I thought the newer tweeters sounded brighter. Now that they are all working together, as it were, the differences have seemed to fade away. Would it be worth the effort to buy the new poly caps for all the crossovers and replace the last set with the newer poly domed tweeters?? Part of me is tempted to pull the newer tweeters out and refit the originals. Oh and please let’s not entertain the notion of a ‘triple Advent setup’…not just yet at least.;-)

[justw]

I have never heard the poly domes you speak of. That being said, one of the things I like best about my stacked Advents is the midrange quality and imaging. These are in my office about 10 feet away and seperated about 8 feet. The top speakers are "upside down" so the tweeters are closest to each other. The bottom speakers are resting on 2" high spikes to couple them to the floor. They sound as good as I could want. In some ways I prefer them to my main speakers on another system. I wouldn't replace the tweeters in mine with anything else or try to redesign the crossovers. If there is anything that could be called "vintage sound" it definetly comes from a set of Advents driven by a Marantz receiver.

Other than taking each driver out and checking which wire goes where you could play some inter-station hiss from your FM receiver with the mono mode on. Checking one pair at a time then maybe swapping one side's A & B, the hiss should image perfectly between the speakers. If out of phase it will seem to suck out the sound from between the speakers and come from far right & left. I can tell you that while fussing with one pair I inadvertantly connected the woofers out of phase with the tweeters and it ruined the midrange completely.

I am working on a third pair that will probably cause me to search out another Marantz amplifier to power them with. Not sure whether I can stack another pair on those spikes or have to start another stack. Maybe a bi-polar arrangement would work.....

[Doug G.]

Gosh, that would be awful to have to live without music on account of not agreeing on genre. My ex and I didn't always like the same thing but we did have some common interests. And, I played what I liked and she didn't when she was away from home.

Anyway, great to hear that you finally get to experience double Advents!

w gave pretty good methods for determining phase correctness. I guess I will add that bass always suffers when they are out of phase because these are the frequencies affected most. But, as w said, lack of solid imaging is another symptom. If you can get to the insides and make sure all the wires go where they should (+ to + and - to -) I think you can be sure that the speakers will be in phase when connected to the amp properly.

As far as the tweeters go, yes, it has been discussed that all the later tweeters than the early "home made" ones are brighter. Whether this is a good thing or not depends on the listener. It has been said that the highs of the New Advent Loudspeaker set at normal are about the same as the originals set at extended.

Unless you can hear some serious aberations in the response of any of your Advents, I think I would leave the caps alone. This is just my opinion, of course. Others would reccomend changing them simply because of their age. I haven't done anything to mine and they sound great.

Got....to....resist....telling...you....to...do...triples...:^)

Doug

[Guest russwollman]

Hello, shepherd.

The new black-dome tweeters are noticeably better than the originals. I discovered that in an A-B comparison of two pairs of Smaller Advents differently fitted. So I did not hesitate to replace the originals, along with the crossover caps, in the four Advents that make my double system. If you have the funds to spare, then the matter is simple. If not, just enjoy what you have, because there's nothing wrong with it as it is, and enjoyment is very much the thing after your years of deprivation ;-)

Does your question about phase refer to whether or not all four speakers' internal wiring is parallel, so to say, or does it refer to proper connection of speakers to the amp? If it's the latter, just connect each side the same way, "+" from the amp to 8 ohm terminal on the speaker, and "-" from the amp to 0 on the speaker.

I have not noticed an out-of-phase condition among the four Advents (properly connected to the amp) I use in the double setup, and after replacing the xover components, I know all the internal wiring is parallel. I don't think the people at the Advent works ever got really sloppy...

One thing worth having for the double system is a powerful amp. I found a NAD 2600 on eBay (150 watts/channel) and use it along with an old NAD 1700 preamp/tuner in the double system with the speakers wired in parallel. My experience with eBay has been favorable, but there are other sites where you can trade. One is http://www.audiogon.com/. Nothing I listen with is very new. New stuff gets a bad rap these days, and with good reason, I think.

Recently I sent the amp to In-House Service Company in Setauket, NY, for the mod they offer for this series of amps. Their service is great, and they do not dwell in the hoity-toity regions of audiophilia. For a modest outlay, just under $200 (incl shipping both directions), it's a good improvement. See http://www.angelfire.com/art2/stereorepair117/index.html, and click on this link: High-End, Tube, Audiophile and Vintage Equipment.

One more recommendation is a Brick Wall surge protector in an audio grade version. Every now and then, they offer a reduced price. See http://www.brickwall.com/.

All of these additions have made the system very satisfying, though it's hard to quantify the value of each one—except for the tweeters. That was obvious. I'm certainly not trying to make a big consumer out of you. I enjoy mentioning tweaks I've found practical. I hope you feel no lack.

One cheap & easy detail you can do is to isolate the two cabinets in the stack by placing something between the two speakers, some sheet of rubber or something like that.

It's amazing how much the Advents deliver. Classics they certainly are.

[real1shepherd]

Thanx for the input. Back in the late 90's Advent or whatever they were calling themselves at that time, recommended the black, polydome tweeters as a 'reasonable' replacement in sound. I wasn't aware or ebay at that time I I think it was in its infancy anyway. Now, I have a speaker site book marked that also offers these tweeters as a 'replacement' along with the caveat to buy the poly crossover caps to get their real potential.

Yes I heard that yrs ago....to orient the tweeters together for the best sound. My bottom pair are on a spiked stand and I was considering attaching the top to the wall oriented horizontally with the tweeter pair near each other-thanx for that input! At least I know that works...

About the phase issue…I have one of those old test records that tests for that. Giving it some thought, most likely I can come up with a plan.

[real1shepherd]

Thanx Doug...I'm blown away from the sound, so most probably things are OK with regards to phase. I have satellite and there are some pretty substantial music channels on there now-can't really find the rock programming that I like though. Anyway, there are three 'dance music' channels that are way FUN to work the old Advents. I don't have to dance, I just dance the furniture around...lol. I can even tell the difference now between Euro re-mix and domestic..*sigh*.

I begged ya not to mention the 'triple Advent system'....at least not yet.....

[real1shepherd]

Thanx Russ. I'm glad to hear about the poly caps and the newer style tweeters being superior in your experience. I just won a pair of newer style tweeters on ebay and I can now proceed with the upgrade if I decide to.

No, everything is wired correctly. My only hesitation is in the original pair that I re-foamed back in the 90's. I see like with this pair I just bought on ebay, the red wire sides of the woofer have a corresponding + mark on the speaker frame. I'm sure I was careful with the old ones, but it's been too many yrs to remember those marks in there. Speaking of "sloppy assembly" at Advent Corp...one of my crossover caps had never been soldered to the terminal. I see in the site here there was a service bulletin about that. I can't tell you how much grief that wire cause, even ruined an original tweeter in an effort to see why it was cutting out. Oh well......

Thank you for all those links...I did find a small repair place that sells used stuff and have my eye on a Phase Linear 400 and matching pre-amp-another longtime dream of mine short of separate Macs, which I can't afford. Your setup sounds kick ass...great amp! That "Brick Wall" surge protector sounds the way to go as well...considering that one seriously.

[tysontom]

>

>So…I have a couple of questions. First of all, how do I

>determine if all the speakers are in phase?? The other

>question is basically about the tweeter/crossover. One set has

>the newer replacement poly dome, black tweeters, but I didn’t

>buy the poly cap for the crossovers yet. When I was A/B-ing

>the two sets separately, I thought the newer tweeters sounded

>brighter. Now that they are all working together, as it were,

>the differences have seemed to fade away. Would it be worth

>the effort to buy the new poly caps for all the crossovers and

>replace the last set with the newer poly domed tweeters??

>Part of me is tempted to pull the newer tweeters out and refit

>the originals. Oh and please let’s not entertain the notion of

>a ‘triple Advent setup’…not just yet at least.;-)

>

The important thing regarding phase is to be sure that all of the woofers are in phase; the tweeter-woofer out-of-phase relationship is not quite as important (due to the really short wavelengths of higher frequencies). To test the woofers, the easiest way is to use a 1.5-volt flashlight battery with wires connected to the positive and negative terminal. When you touch the "+" battery terminal to the positive terminal on the back of each speaker, the woofer cone should move "out" or away from the cabinet. All four speakers should work this way to be sure that they are in phase.

The apparent improvement in sound by double or "stacked" Advents is due to 3-6dB augmentation in the level of the bass (it doesn't go lower, but it gets louder) due to a phenomenon known as "mutual-radiation impedance," and the wider apparent sound source. It also plays louder and has less distortion. I once heard a "triple" Advent system, but it sounded diffuse and very heavy.

--Tom Tyson

[real1shepherd]

"The important thing regarding phase is to be sure that all of the woofers are in phase; the tweeter-woofer out-of-phase relationship is not quite as important (due to the really short wavelengths of higher frequencies). To test the woofers, the easiest way is to use a 1.5-volt flashlight battery with wires connected to the positive and negative terminal. When you touch the "+" battery terminal to the positive terminal on the back of each speaker, the woofer cone should move "out" or away from the cabinet. All four speakers should work this way to be sure that they are in phase."

What an incredibly easy way to test woofer phase! Thanx Tom. There are some members here that swear to the 'triple Advent system'. I've never had the pleasure or hearing that. My next focus is to replace my own original pair, (which look rough) with another pair of walnut veneer like I just rebuilt from ebay. Cabinets and grill cloths are near perfect and embarrassing my original pair-but not in sound!

[Guest daveshel]

The thing about triples is the need to use 2 amps. I don't have 2 matching amps, and even if I did my preamp does not have independent level controls for its 2 main outs and my amps don't have volume controls. One amp would be playing 2 pairs at 4 ohms and the other amp playing one pair at 8 ohms and I would expect the first 2 pairs would be louder.

I guess the answer is to go with 4 pairs and 2 matching amps.